1. Field of the Invention
The present invention relates to alarm devices, and in particular relates to portable and mechanical burglar alarms for indicating unauthorized entry into doors, windows and the like.
2. Description of the Prior Art
A plurality of prior art arrangements have been disclosed which provide a simple, mechanical burglar alarm for mounting adjacent a door, window or the like to indicate unauthorized entry upon rotational movement of the door about its hinges, or linear motion of the window along the window housing.
For example, Schantz, in U.S. Pat. No. 1,859,345 discloses such an arrangement which employs a rotatable lever arm which alternately engages and disengages a trigger pin directly biased against the alarm bell so as to prevent vibration of the bell until such time as the lever arm is actuated responsive to movement of a door, or window adjacent which the alarm is mounted.
A somewhat similar arrangement is disclosed by Rycraft in U.S. Pat. No. 849,129, which teaches a spring-type lever arm coupled to a similar trigger pin for alternately engaging and disengaging the clacker arm of the bell. See also U.S. Pat. No. 149,375 to Connell.
Ambrose, in U.S. Pat. No. 1,218,038, teaches an arrangement remarkably similar to that disclosed by Shantz, also employing a lever arm and a trigger pin actuated in direct response to the movement of the lever arm. A further disclosure of such arrangements is taught by Lasher in U.S. Pat. No. 160,918.
In U.S. Pat. No. 2,953,366, Demers discloses a lever-actuated gear and crank arrangement for effecting operation of the bell clacker arm. A somewhat similar arrangement is disclosed by Smillie in U.S. Pat. No. 3,955,519.
In U.S. Pat. No. 2,447,527, Olvis discloses a window-mounted alarm system employing a horizontally extending actuator rod which is biased against the window jam so as to detect movement of the window in the vertical direction.